Agronomic practice for the protection of crops and new composition of matter



United States Patent thee 3,$Z6,Z44 Patented Mar. 20, 1952 AGRGNOMICPRACTE CE FOR THE PROTEC'EEQN F CROPS NEW COMPOSITIGN 6F MATTER CharlesR. Youngson, Long Beach, and Cleve A. Ii. Goring, Garden Grove, Califi,assignors to The Dow Chemical tlompany, Midland, Mich, a corporation ofDelaware No Drawing. Filed Oct. 39, 1959, Ser. No. 849,767

9 Claims. (Cl. 16722) The present invention relates to fumigantcompositions and is particularly concerned with a new fumigantcomposition and an agronomic practice for improving the ability of soilto support plant growth.

It is an object of the present invention to provide a new fumigantcomposition. A further object is to supply a new agronomic practice andcomposition for improving the plant growing properties of soil and theability of soil to support the growth of crops. Another object is theprovision of a new method and composition for improving the emergence,seedling growth and the harvest of crop plants. A further object is theprovision of a new method and composition for treating soil to obtainimproved controls of soil-dwelling invertebrate organisms such as wireworms and nematodes. An additional object is the provision of a newmethod and composition for treating soil which will accomplish thestimulation of the growth of crops. Other objects will become apparentfrom the following specification and claims.

The new fumigant composition of the present invention comprises aboutone part by weight of 1,4-dichloro-2- butyne in admixture with fromabout 0.3 to 39 parts by weight of chloropicrin. While this compositionadvantageously may be employed in many types of fumigation operations,it conveniently adapts itself to the treatment of soil or other growthmedia to improve the ability of the soil to support plant growth and tobenefit the plants grown in the treated soil. Such practice protects theplants from the ravages of soil-dwelling invertebrate organisms whichattack their roots and improves the growth and harvest of crop plants.it has also been found that the treatment accomplished changes in thesoil which stimulate the growth and improve the growth characteristicsof crops grown therein. It is among the advantages of the presentinvention that the toxi-cants in the mixture appear to be mutuallyactivating so that a greater than additive, or syner istic, result isaccomplished as regards the effect on the plant growing properties ofthe soil and a control of insect and other undesirable organisms andparticularly invertebrates such as Wire worms and nematodes.

The composition comprising the mixture of toxicants is sufiicientlyincreased in effectiveness so as to permit the edective utilization ofreduced amounts of 1,4-dichloro-Z-butyne and of chloropicrin on soil andthe obtaining of crop yields and controls or" soil-dwelling organismswhich are much superior to those obtained when either of theconstituents of the mixture is employed alone. An additional advantageis that these reduced e'n'ective dosages of the mixture of toxicantsmaterially reduce the hazards of soil residues. Thus, the practice ofthe present invention provides a very desirable economic advantage forthe agriculturalist.

1,4-dichloro-2-butyne and chloropicrin are mobile liquids which boil at162 l65 C. and 112 C. at atmospheric pressure, respectively. Mixtures ofthe compounds are somewhat soluble in many organic solvents and of lowsolubility in water and are adapted to be readily and convenientlydistributed in soil. It is among the advantages of the present inventionthat mixtures of these compounds, while sufficiently persistent toaccomplish the desired efiect upon the soil and upon the soil inhabitingorganisms, dissipate in a reasonable period of time. Still anotheradvantage is that mixtures of these compounds permeate soil for adistance of several inches from the point of application depending uponthe temperature, organic content, moisture content, compactness andphysical consistency of the soil or growth media.

in carrying out the improved agricultural practice of the invention, the1,4-dichloro-2-butyne and chloropicrin may be mixed together and suchmixtures employed directly in parasiticidal quantities for the treatmentof soil. However, the present invention also embraces the employment ofgaseous, liquid or dust compositions containing the mixture of toxicantsand for any fumigant purpose where the composition is useful. Thus, themixture of toxicants may be dissolved in a suitable liquid carrier toprovide compositions adapted to be distributed in soil. Such liquidcompositions may also be employed to fumigate the surfaces of certainfruits, vegetables and grains where these products tolerate thefumigation action. Similarly, the 1,4-dichloro-2-butyne and chloropicrinmay be dispersed on or in a granular or finely divided solid carrier toprovide compositions adapted to be distributed in soil or employed asconcentrates and subsequently diluted with additional inert carrier toproduce the ultimate treating compositions. in a further mode ofoperation, the 1,4-dichloro-2-butyne and chloropicrin may be blendedwith a suitable surface-active dispersing agent with or Without one ormore liquid carriers to provide concentrates suitable for dispersion inwater to prepare soil treating compositions in the form of aqueousdispersions or emulsions.

The compositions of the invention may he prepared in any suitablefashion. Since 1,4-dichloro-2-butyne and chloropicrin are miscible inall proportions, compositions without carriers may be prepared by simplemixing of the components at ordinary temperatures. in the prepa rationof compositions containing a liquid organic carrier,1,4-dichloro-2-butyne and chloropicrin are thoroughly mixed in theliquid organic carrier at convenient temperatures. Suitable organiccarriers include liquid aliphatic and aromatic hydrocarbons such astoluene, xylenes, naphthas and hydrocarbon mixtures derived from thedistillation of petroleum or coal, and other organic solvents, such asacetone. For some fumigation operations such carriers as carbontetrachloride or ethylene dichloride may be employed. In general, it ispreferred to avoid liquid carriers having such low flash points as toconstitute a fire hazard or such high boiling points as to leaveundesired residues after use of the compositions. Depending upon theconcentration of the mixture of toxicants, such augmented compositionsare adapted to be distributed in the soil or otherwise, or employed ascon ceutrates and subsequently diluted with additional carrier toproduce the ultimate treating compositions.

in a preferred embodiment of the invention, selected petroleumdistiilates are employed as liquid carriers. ietroleum distillates usedin such embodiment are carefully fractionated portions boiling almostentirely under 460 F. at atmospheric pressure and having a flash pointabove about F. These fumigant compositions are characterized byexcellent penetrating properties and low fire hazard to the shipper anduser.

In preparing dispersihle concentrate compositions, 1,4-

dichloro-Z-butyne and chloropicrin components are mixed in theproportions previously set forth with a surfaceactive dispersing agentsoluble in the composition with or without the further addition of aliquid organic carrier. The surface-active agents are usually employedin the amount from about 1 to about 20 percent by Weight of the combinedweight of the toxicant mixture and surfaceactive agent. Suitablesurface-active dispersing agents include polyoxyalkylene derivatives ofalcohols, phenols and organic acids; oil-soluble petroleum sulfonates;polyoxyethylene derivatives of glycerol and glycols; and the like.

In compositions in which 1,4-dichloro-2-butyne and chloropicrin aredispersed on or in a granulated or finely divided solid carrier, thecomponents may be added directly to the solid carrier with mechanicalmixing. Alternatively, the components may be combined with one or moreof the aforementioned liquid organic carriers and the resultingcompositions admixed with the solid carrier. Suitable solid carriersinclude silica gel, wood-flour, fullers earth, chalk, gypsum, and thelike. 7

In formulating the compositions, it is essential to maintain proportionsfrom about one part by weight of 1,4- dichloro-Z-butyne to about 0.3 to39 parts by weight of chloropicrin and to provide an effective amount ofsaid mixture in the finished composition in order to obtain the desiredsynergistic effect. The concentration of the mixture of toxicants inorganic solvent compositions employed to supply the desired dosage isgenerally from about 10 to about 85 percent by weight. With aqueouscompositions, the required dosage is generally supplied withcompositions containing from about 1 to about 50 percent, althoughconcentrations of 0.0002 percent by weight may be conveninetly employedin irrigation treatments of soil. In compositions wherein the activemixture is dispersed on a solid carrier, it is generally desirable toemploy from about 1 to about 30 percent by weight of the above mixtureof active ingredients in the finished solid composition. With highcapacity carriers, such as silica gel, the active ingredients may amountto 50 percent by weight or more of the solid composition. In any case,it is desirable to employ sufiicient of the solid carrier so that theliquid composition is sorbed to provide a freeilowing solid mixture. Incompositions to be employed as concentrates, the toxicant mixtureoftentimes is present in a concentration from about 5 to about 95percent by Weight.

The soil may be treated with the toxicant mixture or a compositioncontaining the mixture of toxicants in any suitable fashion. With liquidcompositions, good results have been obtained by depositing the activefumigant mixture at regular intervals beneath the surface of the soil.Such deposition may be accomplished readily by automatic machinery or byhand-operated apparatus. Thus, the active composition may be sprayed orotherwise deposited in a furrow which is subsequently closed to keep theactive agents in the desired zone of the soil to be treated.Alternatively, the liquid compositions may be injected into the soil atpredetermined intervals. In any case, the active composition is usuallydeposited at a depth from abou 4 to about 18 inches below the soilsurface.

In row treatments it is advantageous to place the fumigant compositionat least 12 inches below the surface of the seed bed and to seal in thefumigant by listing the soil or by other suitable means such as ringrollers or press sealers attached behind the applicator. In overallapplications with chisel-type applicators, the fumigant composition maybe applied in uniform treatments 1 to 12 inches apart at a depth of 6 to8 inches. With plowsole applications, it is desirable to employ about 8inches spacing between the furrows and to spray or otherwise introducethe fumigant composition so as to cover the bottom of the furrow. Whereinjection of the active composition at intervals is employed, goodresults are obtained when injecting at intervals from 3 to about 12inches, although somewhat greater intervals may be employed in certaincases. In the above operations, it is desirable to apply the fumigantcomposition after the soil has been worked into seed bed condition andwhen the soil temperature is above 50 F. and the soil moisture contentis sufiicient for seed germination.

In another mode of operation, the fumigant composition in emulsifiableform may be dispersed in Water employed to irrigate the soil. In thismethod, the amount of Water may be varied in accordance with theporosity and water-holding capacity of the soil in order to obtain thedesired depth of distribution of the toxicant mixture.

The amounts of the 1,4-dichloro-2-butyne and chloropicrin composition tobe employed will vary depending upon such factors as the type andcondition of the soil, the varieties and growth stages of soil pests tobe controlled and the particular crop to be planted thereafter. Theessential criterion is to employ an amount for accomplishing the desiredeifect upon the soil-dwelling invertebrate organisms and the plantgrowing properties of the soil. In general, good results are obtainedwhen the mixture of toxicants is distributed in growth media to a depthof from 4 to 12 inches at a dosage of at least one pound per acre. Infield applications, the mixture of toxicants is usually introduced intothe soil at a depth of about 6 inches and at a dosage of from 1 to 50pounds per acre. Where compositions embodying a liquid or solid carrierare used, the amount of composition is adjusted to distributesubstantially the above desribed amounts of the active toxicant mixtureper acre. The required amount of the toxicant mixture in the soil mayconveniently be supplied per acre treated in from about 10 to gallons oforganic solvent carrier, in from 10 to 162,000 gallons or more of theaqueous carrier or in from about 50 to 1,000 pounds or more of the solidcarrier.

In one embodiment of the invention, the treated soil is planted with thedesired crop plant following the distribution of the toxicant compoundsin the soil. Where minimum dosages of the toxicant compounds aredistributed in soil, the treated soil may be immediately planted withthe desired crop. Following the distribution of larger dosages of thetoxicant compounds, it is desirable that any planting operation not becarried out for a period of from several hours to several days, theexact period depending upon the concentration of the toxicant compoundsin the soil and the resistance of the species concerned to thecompounds. Where the mixture of toxicant compounds is employed for thetreatment of the soil adjacent to the root system of established plantshaving resistance to the compounds and in side dressing operations, theexisting vegetation is not unfavorably effected by minimum effectiveconcentrations of the toxicant compounds temporarily present in thesoil.

Illustratively, beneficial results were obtained by injecting acetonesolutions of the active fumigants of the present invention into sandyloam soil naturally infested with root-knot nematodes.

Epecifically, acetone solutions of 1,4-dich1oro-2-butyne andchloropicrin were prepared at concentrations suflicient to providedesired dosages in pounds per acre foot by application of 0.1 milliliterof said solution to grams of soil. The infested sandy loam soil wasplaced in 4 ounce scalable jars, and thereafter treated with theforegoing solutions by injection. The jars of treated soil were thensealed and set aside at about 70 F. for one week.

Following the one week interval the containers were unsealed and thesoil allowed to aerate for one week and thereafter planted with threecucumber seeds. During the subsequent growing period, no adverse efiectattributable to the presence of residual fumigant upon the growth of theseedlings was observed. After the cucumbers had been allowed to grow fora sufficient period that root-knot nematode galls were developed in thevarious containers, the cucumber roots were washed, inspected for gallformation, and noted in the following manner:

Table I TOXICITY OF FUMIGANTS TO ROOT-KNOT NEMATODES Pounds Per AcreFoot Percent Samples Control of Chloropicrin 1, rDichloro Nematodes 2Butyne In a manner identical to that described above, additional testswere run for various mixtures of chloropicn'n and 1,4-dichloro-2-butyneat dosages specified in the following table. The actual control resultsobtained from these tests are compared with Expected control computed inaccordance with the graphical approximation method for similar jointeflfect of ingredients of the mixture, as presented in Wadley, TheEvidence Required To Show Synergistic Action of Insecticides and a ShortCut in Analysis, United States Department of Agriculture, PublicationEP-223, June 1945.

Additionally, compositions of the fumigants containing from one part byweight of 1,4-dichloro-2-butyne and from about 0.3 to 39 parts by weightof chloropicrin are admixed with the following adjuvants: (1) finelydivided inert solids, such as silica gel and the like; (2) emulsifyingand dispersing agents such as dimeric alkylated aryl polyether alcohols,alkyl aryl sulfonates and the like; and (3) low boiling petroleumhydrocarbon distillates, such as Stoddard solvent, Standard Thinner 250,and the like. The amount of such adjuvants employed in thesecompositions may vary from 50 to 99 weight percent of the finely dividedinert solids, from 1 to 20 weight percent of the emulsifying anddispersing agents and from to 90 weight percent of the petroleumdistillates. The compositions obtained with the petroleum distillateshad at least a flash point greater than 100 F., and contain about 15weight percent of the fumigants.

The concentrate compositions as above described are adapted to bedispersed in water to produce aqueous compositions having very desirablewetting and penetrating properties. The latter aqueous compositions andthe above described solvent fumigant compositions are adapted to beemployed to treat soil and to distribute the mixture of toxicantstherein in effective concentrations. The use of such fumigantcompositions gives results comparable to those tabulated above.

The compositions of the present invention as hereinbefore described aredispersed in water to produce a material containing about pounds of therespective toxicants per 200 gallons of ultimate material. Thedispersion, while under agitation, is metered into irrigation water atthe pump outlet at the rate of 2 gallons per 1,000 gal-- lons ofirrigation water. The Water is in a state of tux-- bulent flow as itcomes from the pump which provides for the thorough mixing of thetoxicants therein. About 2 acre inches of irrigation water is appliedper acre to land heavily infested with wire worms and root-knotnematodes to accomplish a wetting of the soil to a depth of about 12inches. Two Weeks after the treatment, the soil is planted. In a checkoperation, adjacent but similarly infested soil is also planted. Eightweeks after seeding, the plots are inspected and representative plantslifted from the soil and their roots examined for evidence of wire wormand nematode attack. The examination indicates a commercial control ofboth soil organisms in the treated soil, with severe infestation in thecheck plots.

The foregoing examples are given for the purposes of illustration only,and are not to be construed as limiting the invention thereto.

Various modifications may be made in the present invention withoutdeparting from the spirit and scope thereof and it is to be understoodthat we limit ourselves only as defined in the appended claims.

We claim:

1. A turnigant composition comprising, as active toxic ingredients,about 1 part by weight of 1,4-dichloro-2- butyne and from about 0.3 to 9parts by weight of chloro picrin, the active toxic ingredients of saidcomposition being mutually activating.

2. A fumigant composition comprising a carrier and dispersed therein asactive toxic ingredients about 1 part by weight of 1,4-dichloro-2-butyneand from about 0.3 to 9 parts by weight of chloropicrin, the activetoxic ingredients of said composition being mutually activating.

3. A composition comprising, as active toxic ingredients, about 1 partby Weight of 1,4-dichloro-2-butyne and from about 0.3 to 9 parts byweight of chloropicrin in intimate admixture with an inert carrier.

4. A composition claimed in claim 3 wherein the active toxic ingredientsare admixed with a finely divided inert solid.

5. A composition claimed in claim 3 wherein the active toxic ingredientsare admixed with a petroleum distillate.

6. A composition claimed in claim 3 wherein the active toxic ingredientsare admixed with a surface-active dispersing agent.

7. A fumigant composition which comprises an aqueous dispersion of thecomposition claimed in claim 3, wherein the active toxic ingredients areadmixed with a surfaceactive dispersing agent and said active toxicingredients being present in the amount of at least 0.0002 percent byweight.

8. In the practice of agricultural economy, the process which comprisestreating soil with a parasiticidal dosage of a composition comprisingabout 1 part by weight of 1,4-dichloro-2-butyne and from about 0.3 to 9parts by weight of chloropicrin.

9. In the practice of agricultural economy, the process which comprisestreating soil with a parasiticidal dosag of a composition comprising asactive toxic ingredients about 1 part by weight of 1,4-dichloro-2-butyneand from about 0.3 to 9 parts by weight of chloropicrin in intimateadmixture with a petroleum distillate.

References Cited in the file of this patent UNITED STATES PATENTSYoungson Aug. 26, 1958 OTHER REFERENCES

1. A FUMIGANT COMPOSITION, AS ACTIVE TOXIC IGREDIENTS, ABOUT 1 PART BYWEIGHT OF 1,4-DICHLORO-2BUTYNE AND FROM ABOUT 0.3 TO 9 PARTS BY WEIGHTOF CHLOROPICRIN, THE ACTIVE INGREDIENTS OF SAID COMPOSITION BEINGMUTUALLY ACTIVATING.